Our diets contain roughly 10 times more K1 than K2. And a common misconseption is that we wouldn’t need K2 since the human body would convert K1 into K2. But even though the occurrence is seen on animals, the human body doesn’t seem to do it as effectively. In fact, recent studies suggests that we need to consume the actual K2 form in order to get the benefits (study, study).

The benefits you ask? Well, aside from K2 being awesome for our cardiovascular health and bone density, especially when taken in stack with vitamin D, there’s a bunch of other great effects associated with vitamin K2 supplementation…

…And one of them is the link between vitamin K2 and testosterone:

Vitamin K2 and Testosterone Synthesis

The importance of vitamin K2 is quite a new thing, even to most researchers. And that’s because for a long time, it was believed that the K1 form was all that we need, and that both of the vitamins (K1 and K2) would of have had similar effects.

However few recent studies have proved this to be not true at all. For example: in this study, vitamin K2 supplementation reduced prostate cancer risk by 30%, whereas vitamin K1 had no effect. And then this study where vitamin K2 significantly lowered cardiovascular disease risk by removing calcium deposits from arteries, but vitamin K1 again, had no effect.

The forms of vitamin K2 that we’re most deficient in are the MK-7 and MK-4.

MK-7 is produced inside our gastrointestial system, we can get it from fermented foods. MK-7 is also considered to be very effective in terms of supplementation, as it lasts for roughly three days in the bloodstream.

MK-4 is synthesized all over the body from enzymes (being exceptionally high in the brain and reproductive organs). We can get it through diet by consuming grass-fed animal meats (grain-fed doesn’t contain it). You can also supplement with MK-4, but it only lasts for roughly 8 hours in the bloodstream, and therefore is considered to be worse for supplementation than MK-7.

Still there’s one major reason why I consider the MK-4 form to be superior to the more long lasting MK-7. And that’s because it has a mechanism to increase testosterone production:

a) In this Japanese study, Asagi et al. fed 75 mg/kg of vitamin K2 (MK-4) to male Wistar rats for 5 weeks, while simultaneously measuring the testosterone content from their blood plasma and testicles. The results after the fifth week showed a nice, more than 70% increase in plasma testosterone levels, and an even bigger increase was seen inside the testes (nearly 90%). And as you can see from the pictures below, luteinizing hormone (LH) levels didn’t budge, which probably means that the K2 works by stimulating testosterone production directly inside the ballsack, and not via the brain.

b) In the same study which is presented above, the scientists tested vitamin K2 (MK-4) incubation directly on the testicular I-10 cells inside a petri dish, and found out that the more MK-4 they exposed to the cells, the more testosterone was produced.

c)Another Japanese study from different researchers found out rather similar results. They saw that in male rats, vitamin K2 deficiency reduces testosterone levels significantly, as it messes up with the genes involved in the biosynthesis of testosterone from cholesterol. When these rats were given vitamin K2 (MK-4), their testosterone levels increased rapidly. Similar results were seen in this study.

Conclusion

The studies above are somewhat solid proof of the fact that vitamin K2 (MK-4) has a mechanism of increasing testosterone levels, but so far the mechanism has only been tested on rodents and isolated testicular cells. And the dosages used in the rat studies are abnormally high.

The human equivalent of the dosage in the first study is 12mg/kg. That’s a huge dose. Given that 45 mg’s is considered to be the upper safe limit for humans.

I doubt that you’d ever need to take that high dose of vitamin K2 to actually see the benefits, but when there’s no human studies on its hormonal effects, you can’t really tell…

There will be a time when K2 supplementation is tested similarly in humans, but before it happens, I have no problem supplementing with 30-45 mg’s of potent vitamin K2 (affiliate link) once every few days, just to maintain heart and bone health. And if there’s a bonus testosterone boost happening in the background, I wouldn’t mind at all 😉

he ali, i am enjoying your blog a lot, keep up the good work. The reason i am writing this email is because i am worried about my facial/body structure. I am about to turn 14 years old, i am 175 cm (5’9) 63 kg, but my body and face appear somewhat feminine. My shoulders ARE wider than my hips ( shoulders= 18 inches/45 cm, hips 32 cm 13 inches), but my clavicle is narrower, my ribcage and chest is also smaller than my hips. i have been experiencing low libido, low energy, no morning erections, depression for quite a long time, thought i have started puberty for aprox. 2 years, i have inch of leg hair, pubes, a bit is starting to grow on my chest and arms, i also have 2-3 long hairs on my chin, and a light moustache. i did lab, and my t is 651 ng/dl and 12.3 (something, range is 4.2-42), i do sports 3 times per week sometimes every day ( swimming and mma ), i am very worried that i look feminine, and i think that i might have been exposed to high levels of estrogen before puberty ( however my ring finger is significantly longer than my index), you have started boosting ur t when u were 16, did ur face change?how? if ur face become more square, jaw wider and more angular, chin taller and forehead and brow ridges more prominent? also did ur shoulders widen? do i have a chance to obtain all those qualities ? thanks in advance.
P.S how tall were you at my age?
P.S.S what age did u stop growing in height

Pedro Mendes de Araújo

Calm down dude, you’re 14. Everybody looked slightly feminine at that age. By the way, your height seems normal (above average) for your age, and don’t worry, you’ll change a lot until you are 18. Just keep exercising and taking care of yourself and those changes will occur, trust me.

Eric

I’m a guy at 18 now, I used to be like you. I know this will sound pretty fucking gay but I used to bite my teeth together. Turns out my jaw is actually a lot wider.

Then I started fixing my diet and sleep patterns. If you haven’t done that yet, do it. Also most guys look like that in your age – it takes a while for testosterone to kick in. However, if you want to be on the safe side you follow Ali’s advice!

Mika Nan

also i have a above average/average size addams apple and quite a deep voice too

Eric J Lavin

Where the hell do you find k2 supplements in the 10’s of milligrams range? The most i’ve found are 500 – 1000 micrograms.

I think your calcuation for the human dose is incorrect since it assumes that the rats got 75mg/kg rat instead of 75mg/kg feed

Green Deane

Your gratuitous juvenile terms distract significantly from your work, like putting an icing of manure on a nice cake. That said I take 90 mcg of K2 (M4) a day. Am I concerned? No, in many parts of Japan men consume 10 times that much every day. They ought to be some testi fellows…

Why are u taking MK-4 K2, when K2 MK-7 is way better and MK-4 is stated to be bad as a supplement ?
Lifepsna in boody for Mk-7 is 3 days while MK-4 is only 8 hours, and since the testerone is produced during the night the k2 MK-4 need to be taken just before bed… ?!